RADIATION-OPTICAL PROPERTIES OF RARE-EARTH ION DOPED ALYMINIUM OXYNITRIDE

Pulsed cathodoluminescence and X-ray luminescence spectra of Al50 6N:Ce3+ and A1506N:Eu2+ have been investigated. The concentration dependencies of luminescence intensity have been measured and discussed.Работа выполнена при финансовой поддержке Минобрнауки РФ (стипендия Президента РФ - 2015) и УрФУ (грант молодым ученым - кандидатам наук)

The Kinematic Viscosity of Liquid Copper-Aluminum Alloys

The method of damped torsional vibrations of crucible with liquid under investigation is used for measuring the temperature dependences of kinematic viscosity v of Cu(100-x)Al(x) melts (x = 0-100 at.%) in the range of temperatures t between the liquidus and 1100-1450 degrees C. Unlike the majority of such experiments, the measurements are performed both in the process of heating the sample after its melting and in the course of subsequent cooling. The branching of v(t) curves corresponding to the foregoing modes is revealed below certain temperatures dependent on the composition of sample (viscosity hysteresis). The curves obtained under cooling have a simple exponential shape predicted by activation theories of viscous flow. The obtained temperature dependences are used for constructing isotherms of kinematic viscosity, on which maxima are observed in the vicinity of stoichiometric concentration of CuAl(3) and composition of Cu-30 at.% Al. For the same compositions, extrema are observed on the concentration dependence of activation energy of viscous flow

The Kinematic Viscosity of Liquid Copper-Aluminum Alloys

The method of damped torsional vibrations of crucible with liquid under investigation is used for measuring the temperature dependences of kinematic viscosity v of Cu(100-x)Al(x) melts (x = 0-100 at.%) in the range of temperatures t between the liquidus and 1100-1450 degrees C. Unlike the majority of such experiments, the measurements are performed both in the process of heating the sample after its melting and in the course of subsequent cooling. The branching of v(t) curves corresponding to the foregoing modes is revealed below certain temperatures dependent on the composition of sample (viscosity hysteresis). The curves obtained under cooling have a simple exponential shape predicted by activation theories of viscous flow. The obtained temperature dependences are used for constructing isotherms of kinematic viscosity, on which maxima are observed in the vicinity of stoichiometric concentration of CuAl(3) and composition of Cu-30 at.% Al. For the same compositions, extrema are observed on the concentration dependence of activation energy of viscous flow

Fluorescence Mode XANES Spectroscopy as a Powerful Tool for Redox-Isomerism Studies in Ultrathin Films

Redox-isomerism, i.e., intramolecular electron transfer that results in isostructural compounds with different charge distribution between metal center and ligands, and thus in their different physico-chemical characteristics, attracts considerable interest from the standpoint of development of novel molecular devices. However, direct determination of the valence states of the coordinating cations remains an urgent task. In the present work on the example of cerium bis-tetra-15-crown-5-phthalocyaninate it was shown that synchrotron source X-ray absorption near edge structure spectroscopy in fluorescent mode is a powerful method that allows to directly observe valence states of the metal cations in redox-isomeric materials even in ultrathin single-layer Langmuir-Blodgett films, which are notably hard to study due to extremely small amounts of matter and low dimensionality

Genome-wide RNAi screen of Ca(2+) influx identifies genes that regulate Ca(2+) release-activated Ca(2+) channel activity

Recent studies by our group and others demonstrated a required and conserved role of Stim in store-operated Ca(2+) influx and Ca(2+) release-activated Ca(2+) (CRAC) channel activity. By using an unbiased genome-wide RNA interference screen in Drosophila S2 cells, we now identify 75 hits that strongly inhibited Ca(2+) influx upon store emptying by thapsigargin. Among these hits are 11 predicted transmembrane proteins, including Stim, and one, olf186-F, that upon RNA interference-mediated knockdown exhibited a profound reduction of thapsigargin-evoked Ca(2+) entry and CRAC current, and upon overexpression a 3-fold augmentation of CRAC current. CRAC currents were further increased to 8-fold higher than control and developed more rapidly when olf186-F was cotransfected with Stim. olf186-F is a member of a highly conserved family of four-transmembrane spanning proteins with homologs from Caenorhabditis elegans to human. The endoplasmic reticulum (ER) Ca(2+) pump sarco-/ER calcium ATPase (SERCA) and the single transmembrane-soluble N-ethylmaleimide-sensitive (NSF) attachment receptor (SNARE) protein Syntaxin5 also were required for CRAC channel activity, consistent with a signaling pathway in which Stim senses Ca(2+) depletion within the ER, translocates to the plasma membrane, and interacts with olf186-F to trigger CRAC channel activity